ProMED
http://www.promedmail.org

Source: Agroscope [in German, trans. & summ. Mod.DHA, edited]
https://www.agroscope.admin.ch/agroscope/de/home/aktuell/newsroom/2024/05-22_kraut-knollenfaeule-bei-kartoffeln-beaempfen.html
Currently, several outbreaks of late blight are being observed in potato fields.
Late blight, caused by _Phytophthora infestans_, is the most widespread disease of potato crops. Without control measures, for susceptible cultivars a whole crop can be destroyed completely in just a few days.

Using the Agroscope PhytoPRE system, disease foci can be quickly recognised nationwide, and protective measures can be applied to crops in time. The system provides current general and regional information together with recommendations for suitable control measures.
--
Communicated by:
ProMED

[Late blight of potato (PLB) and tomato is caused by the fungus-like organism (oomycete) _Phytophthora infestans_ and can cause 100% crop loss. The pathogen can also affect some other solanaceous crops. In potato, it affects leaves as well as tubers; in tomato, it causes lesions and rotting of leaves, stems, and fruits. The disease is favoured by cool, moist conditions. It can spread rapidly within a crop and destroy it within a few days. Under favourable conditions, epidemics in tomatoes may be even more rapid than in potatoes.

The pathogen is spread by plant material (including potato seed tubers, tomato transplants, plant debris, volunteer crop plants), mechanical means (including human and insect activities), wind, and water. Disease management requires an integrated approach; it may include removal of pathogen reservoirs, crop rotation, preventative fungicide treatments of planting material, as well as fungicide sprays of crops. Farm-saved or uncertified seed tubers have often been reported as sources of PLB outbreaks. Certified clean planting stock and management strategies for fungicide resistance of the pathogen are considered vital to control late blight outbreaks. Commercial crop cultivars vary in susceptibility to late blight. Development of resistant cultivars is being counteracted by the adaptability of the pathogen.

Late blight is considered an increasing problem worldwide. Considerable variation in aggressiveness between different pathogen strains has been observed, but more virulent strains are emerging frequently. The presence of both A1 and A2 mating types of the pathogen increases the chances of strains with additional fungicide resistances and increased yield losses developing.

Pictures
Late blight on potato:
https://onvegetables.com/wp-content/uploads/2018/08/Potato-late-blight-No-halo.jpg,
https://www.thompson-morgan.com/static-images/tandm/static-articles/how-to-stop-potato-blight/what-is-potato-blight.jpg and
https://farm1.static.flickr.com/81/281344513_74bbffe5fe.jpg
Late blight on tomato:
http://ipm.illinois.edu/ifvn/volume15/images/tomato_late_blight.jpg
Microscopy of PLB-infected cells:
https://micro.magnet.fsu.edu/optics/olympusmicd/galleries/brightfield/images/potatoblight.jpg

Links
PLB information with time lapse of PLB symptom development vs. healthy:
https://www.agroscope.admin.ch/agroscope/de/home/themen/pflanzenbau/ackerbau/kulturarten/kartoffeln/krankheiten/kraut-knollenfaeule.html (incl. disease cycle)
Information on late blight:
https://gd.eppo.int/taxon/PHYTIN (with photo gallery),
https://doi.org/10.1079/cabicompendium.40970,
https://cropscience.bayer.co.uk/threats/diseases/potato-diseases/late-blight/,
https://cipotato.org/press_room/blogs/combating-late-blight/ and
https://www.gov.mb.ca/agriculture/crops/plant-diseases/print,mgmt-late-blight-potatoes.html
_P. infestans_ taxonomy and synonyms:
http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=232148 and
https://www.speciesfungorum.org/GSD/GSDspecies.asp?RecordID=232148
PhytoPRE:
https://www.phytopre.ch/
Agroscope:
https://www.agroscope.admin.ch/agroscope/en/home.html
- Mod.DHA]